You're upper intake manifold may be starting to fail. This allows coolant into the combustion chamber. Have you noticed excessive steam coming out of the exhaust? Is the coolant level low? If the answer to either of those questions is yes then you should remove the spark plugs & see if they're wet with coolant. You could also remove the air filter housing & see if there's coolant inside.
If everything above looks ok then here's what you need to check for a no-start condition:
Spark at all three coils. You can remove the spark plug wires from one coil at a time & watch for spark while someone cranks over the engine. The spark should be strong enough to jump from one post to the other. Check all three. If you have spark the crank sensor is probably fine.
Check for fuel at the rail. Turn the key to run a few times & then press in on the schrader valve. The fuel should spray out not dribble out. Position your hands so the fuel can't spray you in the face.
Check for fuel injector pulse. You can purchase a node light or use a #194 light bulb. Just remove the wiring connector from an injector & connect the node light or pull the wires away from the base of the #194 bulb & insert. Watch for the bulb to pulse as someone cranks over the engine.
If you still haven't found anything wrong try starting with the MAF sensor unplugged. If it still won't start I'd pull the plugs & see if they're wet, dry, black or white. Let us know what you find.